Floorboard (noun)

1. A board forming part of the floor of a building.
2. A board or a set of boards making up the flooring of a vehicle, such as a car or a truck.

Origin:

Floor + board.

Examples:

1. He removed a loose floorboard to access the crawl space.
2. The floorboards creaked as she walked across the room.
3. She had to replace the rotting floorboards in her porch.
4. The mechanic lifted the car"s hood and found a rat"s nest in the floorboards.
5. He heard a squeaking noise coming from the floorboards of his car.